Amino acid profiling of acid tolerance enhanced lactic acid bacterium, Leuconostoc mesenteroides subsp. mesenteroides mutant strain
- 주제(키워드) Amino acid profiling of acid tolerance enhanced lactic acid bacterium , Leuconostoc mesenteroides subsp. mesenteroides mutant strain
- 발행기관 아주대학교
- 지도교수 Pyung Cheon Lee
- 발행년도 2018
- 학위수여년월 2018. 8
- 학위명 석사
- 학과 및 전공 일반대학원 분자과학기술학과
- 실제URI http://www.dcollection.net/handler/ajou/000000027863
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Lactic acid, produced by lactic acid bacteria, is a beneficial product applied in food industry and biotechnology. Metabolic engineering aims to increase the production of lactic acid in lactic acid bacteria. However, the pH of living environment of cell would be decreased because of the accumulation of lactic acid which might lead to cell death. So, adaptive evaluation was applied to increase acid tolerance of lactic acid bacteria. To analyze the difference between enhanced acid tolerance bacterium and wild type, metabolomics was applied as it explores mechanism of biology by analyzing change of metabolites in biological system after exogenous stimulation or genetic modification. As end product, intermediate and precursor of many metabolic pathway, amino acids were chosen as target metabolites. We investigated a standard method, including standard amino acids analysis, intracellular metabolites extraction, metabolomics data analysis, to study the possible reason in enhanced acid tolerance of mutant strain.
more목차
Abstract…...……………………….………………………………………………. i
TABLE OF CONTENTS………………...…………………………………….…ii
LIST OF TABLES……………….……………………………………………….iv
LIST OF FIGURES................................................................................................v
1. Introduction……………………………………………………………………..1
2. Materials and Methods…………………………………………………………7
2.1 Bacterial strains and cultivation...…………………….………………………7
2.2 Chemicals and standards………………..…………………………….………7
2.3 Cell dry weight……………………......…………………………..…..………8
2.4 Sampling and quenching of cell….....…………………………..…..…...……8
2.5 Evaluation of extraction solvent…...…..…………………………..…………8
2.6 Evaluation of bead-beating cycles…………………………….…....………..9
2.7 Sample preparation for GC MS analysis…………….……………...………...9
2.8 Metabolites analysis with GC MS……………………………………..……10
2.9 Production of lactic acid bacteria analysis with HPLC……………..…….…10
2.10 Data processing and statistical analysis………………………...……….…..11
3. Results and discussion…...……………………………………………………13
3.1 Identification and quantification of standard amino acids……….….………13
3.2 Cell collection and preparation……………………….......................………18
3.3 Evaluation of extraction solvent………………………………… …………18
3.4 Evaluation of bead-beating cycles…………………………………. ...…….21
3.5 Amino acids profiling analysis in L.mesenteroides cell………….….………22
3.6 Multivariate analysis………………….……………………………….…….25
3.7 Identification of significantly important amino acids…………………….…30
3.8 Amino acids profiling in L.mesenteroides cell …….…..……………………34
4. Conclusion………………...………………...……………………………….…38
5. References………………………………………………………………...……39
